"that cat just waltzed in and made himself at home" Cats will do that, Chico. You must evict him quickly so he won't think it's really his place, but even then, he'll still visit. Cats are like that...

Chico, you go tell that kitty to move his furry bum. If he gives you any trouble, let me know and I'll send reinforcements to ya! My Cooper is a battle worn veteran with the scars to prove it, and he can sure scare that cat out of a hidey box for ya!